This is ongoing research and development. The capability to calculate the distribution of absorbed dose produced by photon beams and electron beams to the most general characteristics is fundamental to radiotherapy. The radiation field model has been described before. It takes as a basis the empirical distributions along three mutually perpendicular reference lines in a "master field." This concept is applied to the beam-modifying devices as well. One virtue of this approach is that it requires few experimental data and thus can be implemented very easily. The implementation of our photon beam treatment planning programs on a Macintosh II system is continuing. The project is nearing completion for photon beams; an extensive manual with several levels of user guidance has been prepared. The general approach, in particular many "tools" will be directly applicable to other applications, including monoclonal antibodies dosimetry and imaging.